This is a 16-week research study in which participants suffering from Social Anxiety Disorder (SAD) will receive Sertraline (a medication FDA approved for the treatment of SAD) for the first 8 weeks. If a participant remains symptomatic, he/she will enter the second phase of the study in which he/she continues taking Sertraline but also randomly receives either Seroquel or placebo in conjunction with Sertraline for additional 8 weeks. The purpose of this study is to determine the efficacy of adjunctive Seroquel in treating SAD.